Landau Level Splittings, Phase Transitions, and Nonuniform Charge Distribution in Trilayer Graphene Journal Article

Author(s): Campos, Leonardo C; Taychatanapat, Thiti; Serbyn, Maksym; Surakitbovorn, Kawin N; Watanabe, Kenji; Taniguchi, Takashi; Abanin, Dmitry A; Jarillo-Herrero, Pablo
Article Title: Landau Level Splittings, Phase Transitions, and Nonuniform Charge Distribution in Trilayer Graphene
Abstract: We report on magnetotransport studies of dual-gated, Bernal-stacked trilayer graphene (TLG) encapsulated in boron nitride crystals. We observe a quantum Hall effect staircase which indicates a complete lifting of the 12-fold degeneracy of the zeroth Landau level. As a function of perpendicular electric field, our data exhibit a sequence of phase transitions between all integer quantum Hall states in the filling factor interval -8<ν<0. We develop a theoretical model and argue that, in contrast to monolayer and bilayer graphene, the observed Landau level splittings and quantum Hall phase transitions can be understood within a single-particle picture, but imply the presence of a charge density imbalance between the inner and outer layers of TLG, even at charge neutrality and zero transverse electric field. Our results indicate the importance of a previously unaccounted band structure parameter which, together with a more accurate estimate of the other tight-binding parameters, results in a significantly improved determination of the electronic and Landau level structure of TLG.
Keywords: Quantum Hall effect; Single particle; Band structure parameters; Bilayer Graphene; Charge neutrality; Filling factor; Integer quantum hall state; Theoretical modeling; Transverse electric field
Journal Title: Physical Review Letters
Volume: 117
Issue 6
ISSN: 1079-7114
Publisher: American Physical Society  
Date Published: 2016-04-01
Sponsor: This work has been primarily supported by the National Science Foundation (DMR-1405221) for device fabrication and transport, and partly by ONR Young Investigator Award N00014-13-1-0610 for data analysis.
DOI: 10.1103/PhysRevLett.117.066601
Open access: yes (repository)